1. Field of the Invention
The present invention relates to a support structure of a loudspeaker unit and a loudspeaker system. More particularly, the present invention relates to a support structure of a loudspeaker unit enabling a construction in which vibrations of the loudspeaker unit are prevented from being transmitted to a loudspeaker cabinet so that the quality of sound can be improved, and a loudspeaker system.
2. Description of the Relevant Art
FIG. 5 is a sectional side view schematically showing a conventional loudspeaker system.
A loudspeaker system 50 comprises a loudspeaker unit 60 consisting of a cone 61, a voice coil 62, a magnetic circuit 63, a frame 64 and associated parts, and a box-shaped loudspeaker cabinet (hereinafter, simply referred to as the cabinet) 70 in which the loudspeaker unit 60 is assembled. The outer region of the frame 64 of the loudspeaker unit 60 is fastened to the rim of an opening 71 at the front of the cabinet 70 by using screws 72.
In such loudspeaker system 50, since the loudspeaker unit 60 is directly fastened to the cabinet 70, the mounted condition of the loudspeaker unit 60 on the cabinet 70 is stable. As a result, even if the cabinet 70 is caused to tilt or topple over, the loudspeaker unit 60 is unlikely to come off the cabinet 70. In addition, the orientation of its installation (such as a portrait or landscape orientation) and the like can be changed to suit the preferences of a user.
However, while the loudspeaker unit 60 is driven, vibrations of the cone 61 are directly transmitted through the frame 64 to the front of the cabinet 70, so that the whole of the cabinet 70 vibrates. That creates undesired sounds (sounds which do not pertain to original signals), which cause degradation of the quality of sound (e.g. unclearness of sound).
In order to solve the above problem, for example, a loudspeaker system described in the Japanese Kokai No. 1999-355876 has been proposed. FIG. 6 is a sectional side view schematically showing the loudspeaker system disclosed in this publication.
A loudspeaker system 50A comprises a cabinet 70A having an opening 71A at the front thereof for allowing a loudspeaker unit 60A to be exposed, a column 73 extended upwardly from the center portion of the inside bottom of the cabinet 70A, a balance member 74 having a shaft 74a supported by a pivot 73a on the top of the column 73 with a balance construction, a weight 75 fixed for balancing with the loudspeaker unit 60A in the position opposite to the loudspeaker unit 60A with the balance member 74 therebetween, and an elastic body 76 fitted between the opening 71A of the cabinet 70A and the loudspeaker unit 60A.
Using such loudspeaker system 50A, vibrations originating from the loudspeaker unit 60A are absorbed by pendulous movements of the balance member 74, and the energy of vibrations unsuccessfully absorbed thereby is transmitted from the balance member 74 to the column 73 so as to be grounded. As a result, it is possible to prevent unclearness of sound from being caused by the vibrations during operation of the loudspeaker unit 60A being transmitted to the cabinet 70A.
However, the loudspeaker system 50A described in the above publication has such an unstable support structure comprising the column 73 and the balance member 74, so that when the cabinet 70A is caused to tilt or topple over, the shaft 74a of the balance member 74 is likely to come off the pivot 73a of the column 73. As a result, there is a possibility that the loudspeaker unit 60A will come off the opening 71A and be unable to be arranged in its original position. Furthermore, there is a possibility that its internal wiring will be broken, or that the loudspeaker unit 60A itself will be broken. The mounted condition of the loudspeaker unit 60A is less stable, and the orientation of installation of the cabinet 70A cannot be changed.